Document WO 2006070059 A1, which is incorporated by reference, describes a rotation rate sensor for measurement of rotary movements about the y axis. This consists of two seismic masses which oscillate about the z axis (at right angles to the substrate plane) in antiphase about their center of gravity, during the drive mode. In the case of a rotation rate about the y axis, both masses oscillate about the x axis in antiphase about their center of gravity—read mode. This arrangement is relatively resistant to external disturbances, because the overall center of gravity of the arrangement remains at rest during the drive mode, and the sensor is therefore insensitive to design influences. Furthermore, by virtue of their arrangement, both modes—drive mode and read mode—cannot, or can scarcely, be excited directly by external linear excitations or by external rotational excitations.
Document WO 2006113162 A1, which is incorporated by reference, describes a rotation rate sensor for measurement of rotor movements about the z axis. This consists of four seismic masses which oscillate in the x direction during the primary movement or drive mode, such that respectively directly adjacent masses move in antiphase. In the case of a rotation rate about the z axis, the four seismic masses oscillate in the y direction such that respectively directly adjacent masses move in antiphase. This arrangement is also quite resistant to external disturbances, since the overall center of gravity of the arrangement remains at rest during the primary movement, and the sensor is therefore insensitive to design influences. Furthermore, by virtue of their arrangement, both modes—drive mode and read mode—cannot be excited directly by external linear excitations or by external rotational excitations.
The documents WO 2004097432 A1, WO 2008021534 A1, DE 102006052522, DE 102005051048, U.S. Pat. No. 6,892,575, EP 1832841 and WO 2008051677, which are all incorporated by reference, describe sensors which can simultaneously measure rotary movements about the x axis and about the y axis—that is to say no rotary movements at right angles to the base surface of the substrate which, according to the example, is parallel to the x and y axes. The sensor principles mentioned are single-chip solutions; that is to say the sensor elements for measurement of the orthogonal rotation rates are located on the same monolithic silicon chip. Furthermore, they have the common feature that only a single primary movement is excited for both sensitive axes. This saves control-system complexity; furthermore, the chip area is smaller than in the case of two separate sensors. In the case of a Coriolis force, a rotary movement about the x or y axis excites oscillations with movement components in the z direction. If it is intended to use these sensors to measure rotation speeds about the z axis, the sensors must be installed by means of a construction and connection technique, that is to say they must be mounted at 90° with respect to the planar preferred direction—the wafer plane. This leads to additional costs.
The document EP 1918723, which is incorporated by reference, proposes a gyroscope which can simultaneously measure rotary movements about the x and z axes. This is also a single-chip solution with a single primary mode or drive mode. However, this sensor has the disadvantage that both read modes—also referred to as the secondary (detection of the rotation about the z axis) and tertiary (detection of the rotation about the x axis) modes—can be excited directly by rotational movements, and this leads to the sensor being sensitive to disturbances caused by environmental influences.
Document WO 9817973 A1, which is incorporated by reference, proposes a three-axis gyroscope. In this case, in the drive mode, four masses which are each offset through 90° oscillate in the radial direction. This arrangement can distinguish between Coriolis forces in all three spatial directions. However, the individual masses are not directly connected to one another, as a result of which the individual masses are deflected away from the substrate plane, for example in the event of linear accelerations at right angles to the substrate plane.